1. Field of the Invention
This invention relates to improvements in apparatus for moving objects and more particularly, but not by way of limitation, to adjustable roller means for moving objects in a longitudinal and/or rotational direction, and for controlling the rate of speed of movement thereof.
2. Description of the Prior Art
It is frequently desirable to move objects in a longitudinal and/or rotational manner, particularly during instances wherein the objects are being treated, or the like. For example, in a pipe coating operation as set forth in my aforementioned co-pending applications, pipe sections are moved in end-to-end sequential relation through the various steps of the coating operation. It is important that the individual pipe sections be moved continuously in a longitudinal direction, and it is also important that the pipe sections be rotated about their own longitudinal axes during the longitudinal movement thereof. Pipe sections are frequently relatively long and may be of relatively large diameters; and as a consequence, the movement thereof creates many problems. The overall situation is aggrevated in a pipe coating operation since it is important that the outer periphery of the pipe not be contacted subsequent to the actual application of the coating material thereon, but it is still important that the pipe sections being coated are moving longitudinally and rotationally in order to achieve an efficient and thorough coating of the pipe.
As set forth in my aforementioned applications, the pipe sections being coated may be carried by wheeled vehicles which ride freely through the coating steps or sections of the system and are supported on the vehicles by means of end plug means which engage only the inner periphery of each pipe section at the opposite ends thereof. The plug means is freely rotatable, and thus the pipe sections may be rotated and moved longitudinally as they are carried by the vehicles. However, it has heretofore been difficult to accomplish this combined longitudinal and rotational movement for pipe sections during a coating operation.